• Korean Journal of Soil Science and Fertilizer
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• v.48 no.2
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• pp.119-124
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• 2015

Pyoverdines (PVDs) are organic compounds produced by the fluorescent Pseudomonads under iron starvation conditions. Among the isolated rhizosphere pseudomonads strains, P. putida KNUK9 showed the highest production of PVDs and its production reached to 62.81% siderophores units. DNA isolation, ligation, PCR amplification, and transformation using E. coli $DH5{\alpha}$ cells were carried out for preparing the strong pyoverdine producer strains. We detected seven genes playing the fundamental roles in the pyoverdine metabolism in Pseudomonads. According to data and analysis obtained from the study, we deduced that the strain P. putida KNUK9 contains the essential genes required for pyoverdine biosynthesis.

• Journal of Environmental Science International
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• v.26 no.1
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• pp.11-21
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• 2017

In this study, bacterial growth was assessed by flow cytometry analysis of fluorescent probes-stained bacteria. Flow cytometry has many advantages of rapid analytical time, a low standard deviation, and highly sensitive detection of live and Dead E.coli over colony forming assay. When untreated bacteria were stained by using Thiazole Orange (TO) and Propidium Iodide (PI), double staining had a short analytical time as compared with that of single staining while its error rate was similar to that of single staining. Through double staining experiments, it was determined that optimal concentrations for TO and PI staining were 420 nM and $9.6{\mu}M$, respectively.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1173-1176
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• 2009

• Journal of Sensor Science and Technology
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• v.14 no.5
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• pp.308-312
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• 2005

We present a microfluidic chip designed for the detection of antibody by using quantum dots fluorescence and a microbead-based assay. A custom designed PDMS microfluidic chip with multi-layer channel is utilized for capturing microbeads; antibody injection into each micro-well; QD injection; and fluorescence detection. The experiment using the fabricated microfluidic chip has been performed on solutions with various concentrations of antibody and has shown correlated fluorescent intensities.

• Toxicological Research
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• v.34 no.1
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• pp.1-6
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• 2018

The purpose of this study was to detect cell death in the liver of mice treated with thioacetamide (TAA) using fluorescence bioimaging and compare this outcome with that using conventional histopathological examination. At 6 weeks of age, 24 mice were randomly divided into three groups: group 1 (G1), control group; group 2 (G2), fluorescence probe control group; group 3 (G3), TAA-treated group. G3 mice were treated with TAA. Twenty-two hours after TAA treatment, G2 and G3 mice were treated with Annexin-Vivo 750. Fluorescence in vivo bioimaging was performed by fluorescence molecular tomography at two hours after Annexin-Vivo 750 treatment, and fluorescence ex vivo bioimaging of the liver was performed. Liver damage was validated by histopathological examination. In vivo bioimaging showed that the fluorescence intensity was increased in the right upper part of G3 mice compared with that in G2 mice, whereas G1 mice showed no signal. Additionally ex vivo bioimaging showed that the fluorescence intensity was significantly increased in the livers of G3 mice compared with those in G1 or G2 mice (p < 0.05). Histopathological examination of the liver showed no cell death in G1 and G2 mice. However, in G3 mice, there was destruction of hepatocytes and increased cell death. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining confirmed many cell death features in the liver of G3 mice, whereas no pathological findings were observed in the liver of G1 and G2 mice. Taken together, fluorescence bioimaging in this study showed the detection of cell death and made it possible to quantify the level of cell death in male mice. The outcome was correlated with conventional biomedical examination. As it was difficult to differentiate histological location by fluorescent bioimaging, it is necessary to develop specific fluorescent dyes for monitoring hepatic disease progression and to exploit new bioimaging techniques without dye-labeling.

• Journal of the Korean Vacuum Society
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• v.8 no.1
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• pp.13-19
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• 1999

Total reflection X-ray fluorescence spectroscopy using synchrotron radiation source called as TRSFA was explored to achieve high sensitivities to impurity metals on Si wafer surface. It consists of monochromating part to select a specific wavelength, slit part to shield direct beam and to control monochromated beam, and main chamber to dectect fluorescent X-ray counts of impurities on si wafer. Monochromated X-ray of 10.90 KeV was selected and the optimum total reflection condition on silicon wafer was obtained through tuning the dead time and fluorescent X-ray count of Si and Fe. TRSFA system could increase the sensitivity as high as 50 times in comparision with TRXFA using normal X-ray source. But the trend was varied since the surface conditions of Si wafers and, therefore, the reflectivities were different. Furthemore, there seems to be a promising path to reaching a detection limit useful to the next generation metal impurities control, because Fe impurity below to the $5\times10^{9}\textrm{atomas/cm}^2$ can be detectable through the developed TRSFA system.

• Journal of Adhesion and Interface
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• v.14 no.1
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• pp.13-20
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• 2013

Palladium plays a pivotal role in the production of dental and medicinal devices, medicinal substances, jewellery, automobile and high-performance adhesives. Despite the frequent and fruitful use of such reactions, one major setback is the high level of palladium in the resultant compounds which can harm the human body. Among the palladium species, $PdCl_2$ is the most toxic. As a consequence it is desirable to detect the $Pd^{2+}$ cations by fluorescence spectra because it can provide an operationally simple and cost-effective detection method together with high sensitivity and selectivity. Herein, an ${\alpha}$-carbonyl substituted pyrene derivative, ${\gamma}$-oxo-1-pyrenebutyric acid (OPBA), was demonstrated to be a highly sensitive and selective fluorescent probe for $Pd^{2+}$ among the metal cations examined in aqueous solutions.

• Journal of Sensor Science and Technology
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• v.25 no.1
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• pp.51-56
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• 2016

This study evaluates the performance of an optical sensor and measurement system (CMA-24) which can analyze the fluctuation of dissolved oxygen and pH simultaneously. In the optical sensor system, the fluorescent materials, Rudpp and HPTS which are sensitive to dissolved oxygen and pH, respectively, are coated on the bottom of a 24-well -plate by the sol-gel technology. The detection times of the emission light of the oxygen sensor were $4,186{\pm}13.90{\mu}s$ and $4,452{\pm}36.68{\mu}s$ for the dissolved oxygen of 17% $O_2$ and 7.6% $O_2$, respectively. On the other hand, the detection times of the pH sensor were $6,699.43{\pm}14.64{\mu}s$, $6,722.24{\pm}6.21{\mu}s$, and $6,748.52{\pm}2.63{\mu}s$ using pH 6, 7, and 8, respectively. When we determined cellular respiration levels of C2C12 myocytes with CMA-24, $O_2$/pH measurement system, the ratio of the uncoupled to coupled OCR (oxygen consumption rate) was 1.41. The results mean that this CMA-24 system shows almost the same sensitiveness as the commercial system.

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.86-93
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• 2007

In recent tests using tracer have been frequently conducted by fluorescent tracers. In this study, granular activated charcoal (GAC) as a detector for the fluorescent tracers (rhodamine WT and uranine) was investigated through laboratory and field tests. In the laboratory tests, tracer concentrations of rhodamine WT and uranine determined by the GAC were slightly different from those of standard solutions but they were excellent in linearity. Results show that GAC is excellent as tracer detector when concentration of the fluorescent tracers is greater than 10 & micro; g/L whileas no obvious differences in mixed solutions of the two tracers due to interferences. Compared to conventional methods of water sampling, field results shows a high potential of GAC as a tracer in the field. Our results also show that wet analysis is better for the lower concentrations of tracers whileas dry analysis is good for high concentrations of tracers. This study demonstrates that fluorescent tracer detection using the GAC is very useful and economical for a hydraulic connection between target areas and very longer period of the tracer test.

• KSBB Journal
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• v.22 no.1
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• pp.48-52
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• 2007

This study was carried out to establish the optimum disruption condition of a sonificator for the protein toxin for the purpose of developing automatic biological agent detector equipped a sonificator. One of the best-known collisional quenchers is molecular oxygen, which quenches almost all known fluorophores. The sonification does an excellent job of degassing, which decreased the quenching effect and increased the fluorescence quantity. The fluorescence measurement for the protein using 0.7 X fluorescent dye concentration and above must be done in 1 minute and the fluorescence measurement for the protein using 0.3 X fluorescent dye concentration and below has to be done between 2 and 3 minute. The fluorescence quantity of the sonificatied protein sample was much higher that of the non-sonificatied protein sample. Sonificating the sample turned out to be favorable for the fluorescence measurement when measuring at the low protein concentration.